On Wed, May 04, 2022 at 12:46:36AM +0300, Serge Semin wrote: > In accordance with the generic PCIe Root Port DT-bindings the "dma-ranges" > property has the same format as the "ranges" property. The only difference > is in their semantics. The "dma-ranges" property describes the PCIe-to-CPU > memory mapping in opposite to the CPU-to-PCIe mapping of the "ranges" > property. Even though the DW PCIe controllers are normally equipped with > internal Address Translation Unit which inbound and outbound tables can be > used to implement both properties semantics, it was surprise for me to > discover that the host-related part of the DW PCIe driver currently > supports the "ranges" property only while the "dma-ranges" windows are > just ignored. Having the "dma-ranges" supported in the driver would be > very handy for the platforms, that don't tolerate the 1:1 CPU-PCIe memory > mapping and require customized the PCIe memory layout. So let's fix that > by introducing the "dma-ranges" property support. > > First of all we suggest to rename the dw_pcie_prog_inbound_atu() method to > dw_pcie_prog_ep_inbound_atu() and create a new version of the > dw_pcie_prog_inbound_atu() function. Thus we'll have two methods for RC > and EP controllers respectively in the same way as it has been developed > for the outbound ATU setup methods. > > Secondly aside with the memory window index and type the new > dw_pcie_prog_inbound_atu() function will accept CPU address, PCIe address > and size as its arguments. These parameters define the PCIe and CPU memory > ranges which will be used to setup the respective inbound ATU mapping. The > passed parameters need to be verified against the ATU ranges constraints > in the same way as it is done for the outbound ranges. > > Finally the DMA-ranges detected for the PCIe controller need to be > converted into the inbound ATU entries during the host controller > initialization procedure. It will be done in the framework of the > dw_pcie_iatu_setup() method. Note before setting the inbound ranges up we > need to disable all the inbound ATU entries in order to prevent unexpected > PCIe TLPs translations defined by some third party software like > bootloader. > > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> > --- > .../pci/controller/dwc/pcie-designware-ep.c | 4 +- > .../pci/controller/dwc/pcie-designware-host.c | 32 ++++++++++- > drivers/pci/controller/dwc/pcie-designware.c | 57 ++++++++++++++++++- > drivers/pci/controller/dwc/pcie-designware.h | 6 +- > 4 files changed, 90 insertions(+), 9 deletions(-) Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
